Local externalization of phosphatidylserine mediates developmental synaptic pruning by microglia

Synaptic pruning by microglia is necessary for normal brain development.

Microglia are highly motile phagocytic cells that infiltrate and take up residence in the developing brain, where they are thought to provide a surveillance and scavenging function. However, although microglia have been shown to engulf and clear damaged cellular debris after brain insult, it remains less clear what role microglia play in the uninjured brain. Here, we show that microglia activel...

Neuronal exosomes facilitate synaptic pruning by up-regulating complement factors in microglia

Selective elimination of synaptic connections is a common phenomenon which occurs during both developmental and pathological conditions. Glial cells have a central role in the pruning of synapses by specifically engulfing the degenerating neurites of inappropriate connections, but its regulatory mechanisms have been largely unknown. To identify mediators of this process, we established an in vi...

Progranulin Deficiency Promotes Circuit-Specific Synaptic Pruning by Microglia via Complement Activation

Microglia maintain homeostasis in the brain, but whether aberrant microglial activation can cause neurodegeneration remains controversial. Here, we use transcriptome profiling to demonstrate that deficiency in frontotemporal dementia (FTD) gene progranulin (Grn) leads to an age-dependent, progressive upregulation of lysosomal and innate immunity genes, increased complement production, and enhan...

The expression of CD10 by apoptotic lymphocytes is preceded by a pronounced externalization of phosphatidylserine.

Suicidal membrane repair regulates phosphatidylserine externalization during apoptosis.

One of the hallmarks of apoptosis is the redistribution of phosphatidylserine (PS) from the inner-to-outer plasma membrane (PM) leaflet, where it functions as a ligand for phagocyte recognition and the suppression of inflammatory responses. The mechanism by which apoptotic cells externalize PS has been assumed to involve "scramblases" that randomize phospholipids across the PM bilayer. These pu...